Two Hacker Herald RP37 transistor portables 1969.

[Heatercathodeshort]

Two Hacker Herald VHF portables RP37 and RP37A

Another loft find packed away a good while back. They were packed in a cardboard box marked 'Found at tip'. I guess this would have been around 2000/2001 and at the time I did not consider them to be anything special and just wrapped them up and stored them away.

Looking back I remember thousands of radios of all types discarded at the tip over the 20 year period I had permission to clear radio and TV items. To think that thousands of these radios were dumped across the Country just to land fill. Things have changed and now all of these interesting items are crushed for our security.

The first one tackled is the red RP37. A quick examination showed that one of the PP9 batteries had leaked in the past leaving a dark stain on the base of the cabinet. Connecting 18V from my bench power supply produced nothing, not even a click!

Shorting the mains switch did nothing and removal of the separate plug in amplifier soon revealed the problem. A printed track close to the edge of the board had deteriorated due to the battery leakage. This was soon sorted with a short length of insulated wire and a thorough clean.

Success! The RP37 now performed exceedingly well with all stations received with good quality and volume. After a good clean it was obvious that this was a high quality receiver.

The second one proved to be a bit more challenging. This is a Black RP37A. No battery damage here but again completely dead! Removal of the audio amp showed a clean circuit board with nothing out of place. I have a large box of Hacker circuits somewhere but could I find them?

Working blind I removed the two output transistors AC176 and AC128's. Both were S/C. The driver tested OK.

These were replaced with NOS items and the RC37 tested. This time just a low level transistor 'hiss' but no audio output. The Dictograph amplifier connected to the audio input pin of the five way plug produced very high quality sound proving that the fault was definitely in the audio amp.

Checking back along the line I discovered the BC148 audio pre-amp with good audio on it's base but nothing at the collector or emitter. It soon proved to be O/C and fitting a replacement BC108 brought forth high quality audio similar to the earlier RP37. I think the damage was caused by it's owner attempting to supply it with dodgy mains eliminators. They must have been quite expensive to run.

I discovered the pack of Hacker service manuals neatly packed away under 'HACKER' I really should have taken the obvious path first and looked in the filing cabinet.. I have used the RP38 adjustment data to reset RV1 and RV2 for 3m/a and 8.85v respectively and all seems well. I presume it is a similar amplifier.

There is a Hacker label tied to the bottom of the telescopic aerial advertising a carry case at £2.8.0 [£2.40]

Such a pity that Hacker folded. They produced very fine quality equipment but the public won't pay for quality anymore and when they think they have, the innards tell a different story. They should have been taken over by ROBERTS RADIO, a perfect marriage.

Regards, John.

[McMurdo]

they look in nice condition and deserved to be fixed. The VHF heralds being the desirable ones for the obvious reasons, I eat my daily bran flakes to the sounds of a VHF Hacker, although my bedroom Herald is a lowly AM version with its restricted choice of easy listening.

[agardiner]

Nice. These sets sometimes come up on ebay and usually fetch a premium. Lots of Hacker collectors out there and the VHF only sets are sought after.

[Radiocruncher]

Great job John. These are one of the best sounding VHF sets Hacker did and you have cleaned them up very well. Definitely keepers.

Regards

Graham